[Collins] 75A-4 Dial Set Screw Problem

[Jim Walker]

Success!  The common thread answer was "heat."  I borrowed the 5 1/2
inch nozzle from an oil can at work and placed a 3/8 inch piece of fiber
glass tubing over it.  I placed a piece of copper foil between the dial
and the inside of the shaft and placed aluminum foil all around areas
that looked heat sensitive.  I took an UNGER heat gun with a 1/2 inch
nozzle and directed it into the oil can nozzle held almost against each
set screw.  It got hot very quickly (was holding the nozzle with a pair
of pliers).  I gave it about 30 seconds, removed the nozzle and heat gun
and used the XCELITE 99-62 .060 inch spline wrench into the screw.  Each
one popped loose with minimum pressure.

 

I considered the plan B option of loosening the IF timing and PTO gears
but that would have changed the IF tuning timing and PTO frequency
relationship.

 

Thank you to the many helpful responses from the list.

 

Jim 

KZ5AW